Piston for internal combustion engines



Oct. 18, 1932. H. c. EDWARDS PISTON FOR INTERNAL COMBUSTION ENGINES Filed NOV. 15. 1950 I pistons intended Patented Oct. 18, 1932 H ERBERT C. EDWARDS, OF DETROIT, MICHIGAN, ASSIGNOB OF DETROIT, MICHIGAN,

COMPANY,

'ro PACKARD Mo'ron can A CORPORATION OF MICHIGAN PISTON FOR INTERNAL COMBUSTION ENGINES Application filed November 15, 1930. Serial No. 495,957.

This invention relates to improvements in for use in internal combustion engines, and has for its objectthe provision of an engine piston which will assist in maintaining the associated cylinder walls properly lubricated under all working conditions.

Considerable difiiculty has been experienced in connection with the operation of g high speed internal combustion engines, particularly engines developing high tempera; ture such as the Diesel type, by reason of insilflicient lubrication of the cylinder walls and consequent scoring of the cylinder the sticking or seizing of the piston. It is proposed by means of the present invention to dilliiculties by so designing the piston that a film of oil is maintained between the piston and the cylinder regardless of the heat developed while the motor is operated, and particularly between those surfaces of the piston and cylinder which are subjected to the greatest wear by reason of the side thrust exerted by the connecting rod and expansion caused by heat.

In .the accompanying drawing one overcome these form of the invention is illustrated by way of example.

Figure 1 is an elevational view of one form of piston to which the present invention has been applied; and

Figure 2 is a section on the l'ne 22 of Fig. 1.

Referring drawing, it will be observed that the piston selected for illustrating the invention and indicated by the reference numeral 10, is of the type Whch is provided with a plurality of grooves 12 for the retention of the compression rings and a groove 13 adapted to receive an oil ring, but it will be understood that the invention is equally applicable to other types of pistons.

The piston 10 is provided with the usual shallow grooves 16 are formed in the outer Wall of the piston and preferably in the skirt portion inter mediate the oil ring and the compression rings. In the present embodiment of. the invention, four of these grooves are shown,

now more specifically to the.

two being located on each side of the piston intermediate the wrist pin bosses. These grooves are preferably inclined with respect to the axis of the cylinder, as shown in Figure 1 of the drawing, and each such groove communicates at its upper end with an aperture 19 extending through the piston wall'so that communication is, established between the rooves '16, and the interior of the piston. It will be noted that while the pair of grooves 16 on one side of the piston are inclined toward each other, there is no communication between these grooves at their lower ends and accordingly no weakening of the piston results. This feature is particularly important in the construction of a lightweight high speed piston in which the walls are made as thin as possible and in which the provision of intersecting grooves might seriously weaken the skirt portion and result in breakage of the piston and consequent damage to the motor while in operation. Furthermore, this spacing of the adjacent grooves at their lower ends prevents flooding of the cylinder and piston surfaces With oil at this point.

In practice it is found unnecessary to provide lubricating grooves at other points on the circumference of the piston, cally the entire wear on the piston walls occurs at points remote from the wrist pin bosses and seizure oflthe piston and scoring herein, oil will be gathered in the grooves 16 from the cylinder. wall upon inward movement of the piston and such collected oil is spread axiallyalong the cylinder wall upon outward movement. The excess collected oil will flow from the grooves through the openings 19 into the interior of the piston. This arrangement for collectlng 011 insures that the cylinder wallsurface adjacent the since 'practigrooves during the piston movement will be uniformly and regularly lubricated.

It will be observed that the grooves 16 lie entirely within the confines of the outer surface of the piston, or in other Words, the

grooves are so arranged as to communicate with the exposed portions of the cylinder and with the piston interior only through the apertures 19. If these grooves extended to the lower edge of the piston skirt, for instance, the oil film would not be retained on the piston surface but the opposite efiect from that desired would be produced, name- 1y, oil on the piston surface would pass into the grooves and be returned tothe cylinder below the piston.

It will be understood that the foregoing detailed description is intended primarily to illustrate the principles of the invention and that such further modifications of the piston disclosed herein are contemplated as fall within the spirit and scope of the appended claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A piston havin spaced apertures extendlng ton wall and having grooves ton surface, each such groove communicating with one of said apertures only, the adjacent grooves being inclined with respect to the longitudinal axis of the piston and extending from the associated apertures toward the lower end of the piston and toward each other and being spaced apart throughout their length.

2. A piston provided with wrist pin bosses and having circumferentially spaced apertures extending through the wall thereof, said circumferentially through the pispiston being provided with grooves in the outer surface thereof, each groove communicating with an aperture and extending from said aperture away from the head end of the piston and convergent to said grooves and apertures being located on opposite sides of the piston intermediate the wrist pin bosses and lying entirely within the confines of the cylindrical surface of the pis- In testimony whereof ll hereunto afix my signature.

WRBERT C. EDWARDS.

essee? in the outer pis an adjacent groove, 

